System for the rapid change of head on operating machines

ABSTRACT

A system is disclosed for the rapid change of heads in operating machines, such as equipment for the cut and/or decoration of passe-partout, or of items made of cardboard, glass, ceramic or the like. A system according to the present invention couples the head of the machine with a machine arm through a connecting element that contains one or more magnets. Said magnets retain the head connected to the connecting device by attraction, but also allow the head to be easily removed with just one hand.

TECHNICAL FIELD

The present invention concerns the technical sector relative to largeand small-production machines in the field of industrial automation.

The present invention can be applied to machines having a head that mustbe interchanged. In particular, the present invention is hereindescribed with reference to machines that produce a cut and/ordecoration of “passe-partout” or other elements made of cardboard orcorrugated cardboard, glass or ceramic, including existing machines. Thehead of the machine may include a “pen”, or other similar element,instead of a blade.

BACKGROUND ART

Different types of machines include a moving mechanism and a main partcalled “head” that fulfils the desired work. The head can be used forcutting, engraving, drawing or for performing any other operation on apiece that must be worked on. In all these types of machines, it isoften necessary to replace the head with a different head for performinga different type of work. It is therefore important to perform headreplacement rapidly and safely.

In particular, in the paper sector, there are machines that make the cutor the decoration of cardboard, either smooth or corrugated. Similarmachines are also used in the sector of decoration of items made ofglass, ceramic, plastic or other material.

The present description will focus on machines used for the cut ofpasse-partout, in order to highlight a technical sector where thepresent invention can be appropriately used. The “passe-partout” is thean internal frame inserted behind the glass of pictures, with thepurpose of creating a stand-out, generally of constant width between theexternal frame and the subject of the picture, which may be a print,painting, or other.

Shapes and dimensions of the passe-partout can vary, but the most commonones are rectangular.

The material of the passe-partouts is generally white or colored paper,thin enough to be inserted between picture and glass, which must be cutwith a limited mechanical force. Nevertheless, in order to produce thiscut, a suitably directed and sharp blade is required, as well as aprecise speed and approaching direction.

Nowadays, different types of machines exist for this purpose, which canbe briefly described as follows.

Such machines include a main group supporting the cutting headvertically, so that it can vertically moving up and down the item to beworked, including sudden directional changes of the cut. The axialmovement can be either pneumatic, hydraulic or electromechanical,according to the design of the machine. These machines include an enginethat allows the head to rotate, typically an electric engine, which iseasier to be control electronically, and a connecting device fitted onthe output shaft of the engine, so that the engine, through a timingbelt, can transmit the rotation to the head holding the cutting tool.

The head, axially connected to the main group, has a vertical movementwith a shaft along an axis where the connecting device is fitted.

The head of the machine can be mechanically manufactured by means ofseveral known systems and includes a blade for cutting the paper. Thisblade rotates thanks to the connecting device that is axially fittedproviding the blade with the desired changes of direction, withoutfurther raising the head block in case of continuous or radialgeometrical shapes (such as circles, ellipses, etc.), or a linearapproaching stop whenever angles must be formed, forming instead theangle after raising the head.

The transversal motion of the head block can be provided by knownautomatic machines.

The above-described production method offers excellent results both froma qualitative and productive point of view. Obviously, the speed ofproduction depends on many factors.

A problem with prior art systems is the need to replacing the cuttingtool manually, which obviously has different characteristics accordingto the different materials to be cut, the different types of cut or thedifferent types of operations to fulfill.

Using a head as described above, it is also possible to cut packingboxes and with another head it is possible to engrave cardboard in orderto create some grooves that facilitate the closing of the boxes. In thisspecific field, this operation is very difficult and laborious, exceptfor some machines that have two heads (one for a 45° cut, and one for90° cut). Nonetheless, these machines have a high cost because they anadditional axis is required, beyond the standard three axes, for theadditional head.

Sometimes, it is necessary to perform cuts with different slopes, 90° or45° or other degrees. In this case, it is important to replace the headrapidly than with a traditional one-head machine and reduce costs, stillproviding the same technical result as with a machine equipped with moreheads.

In addition, the head can be changed to substitute the blade with pensor other accessories that decorate an item instead of cutting. Yet, thefinal accessory holding the blade, the pen or similar, is changes onmachines known in the art, but this is a slow operation.

Despite the design variations of each machine manufacturer, in order tochange the head it is necessary to have a tool, such as a plug, whichacts on a joint, either a threaded joint, or (conical) friction joint,or having other designs known in the art to date.

Because the head must be carried out frequently, the effectiveness ofthe machine is considerably reduced by these necessary interruptions.Moreover, these substitutions considerably slow down the productionrates, affecting the manufacturing process.

German Patent DE 199 3 8 114 to Dürr Systems GmbH discloses a machinecomprising a fixing element 1 for supporting a support element 3 for atool 2. This machine is particularly used in car factories forperforming operations like the painting or lifting of chassis. Accordingto the solution proposed in this patent, the support tool 3 is connectedto the fixing element 1 by magnetic connection 5, and is adapted toavoid the breakage of the tool 2 in case of accidental hitting againstparts processed by the machine. The structure disclosed is in thispatent is very complex and is not adapted to support a rotating tool andfor a rapid change of the tool itself.

SUMMARY OF THE INVENTION

The present invention avoids the above-mentioned and other drawbacks byproviding a system for replacing simply and rapidly, without the need ofadditional tools such as keys, levers or other, the head of an operatingmachine, in particular of cutting or decorating machines, in order tochange the ancillary equipment connected to the head, like blades orpens, which can be installed from time to time on the rotating head ofsaid machines.

This system can be used on several types of equipment with reactionforces similar to the above described machines, thus, not restrictingthis invention only to the specific sector of paper cutting.

By the term “head” we mean the end portion of the operating arm of amachine, equipped with tools, either for cutting, decorating or other,which act on a predetermined item. By replacing the head, theaccessories applied or integrated to it are replaced as well.

The advantages resulting from the present invention essentially consistin: a faster production rate, regardless of the type of work to be done,for example cuts with different slopes and/or more or less ornatedecorations; a force necessary for removing the head that is very low,therefore the head can be easily removed by any worker just with onehand; providing a component that, after assembly, does not reduce at allthe effectiveness of the device, both in non-operational movements ofangular approach and, above all, in the during normal operation;increasing effectiveness of a component according to the invention bypressure exerted on the tool by axial motion and kept constant byelectrovalves controlled by sensors applied over a supporting wheel; arapid change of tool; perfectly fitting existing machines; applicabilityto machines in different manufacturing sectors; producing any type ofpasse-partout of various shapes (rectangular, circular, elliptical,etc.), possibly after raising and new angular direction of the blade incase of angles.

Reduced to its essential structure and with reference to the figures ofthe enclosed drawings, a system for the rapid change of head in anoperating machine, according to the present invention, includes a deviceproviding a stable attraction between the head (3) and any element overit, like connecting device (2), with said element including at leastone, preferably more than one, magnet or the like having enough force tokeep the head bound even without mechanical block elements.

This system comprises balance elements between said element, like aconnecting device, and said head.

In order to achieve an effective coupling, the head (3), equipped with acutting blade (4) and/or a pen, the element over the head, such as aconnecting device (2), includes at least one, preferably more than one,hole (10) of suitable diameter and thickness proportional to the one ofsaid element, which receives at least one connected magnet (11), of samediameter but slightly shorter, such to avoid any projection on the outersurface.

In on embodiment, the holes (10) and the related magnets (11) arepreferably three.

The magnets can be replaced with other elements capable of forming amagnetic field, such as a solenoid or other similar device. A solenoid,when energized, generates a magnetic field that can also be annulledstopping the passage of electricity. In this embodiment, it is possibleto create even an intense magnetic field that causes no problems to thesuccessive removal of the head, because it can be easily annulled inorder to avoid any obstacle to said operation.

This system is also configured to couple and axially center the head(3), which is equipped with cutting blade (4) or pen or other tool, byproviding a calibrated hole (16), realized on the same head, which fitsduring assembly on the extension of the shaft (8) of the element, suchas a connecting device (2), fitted on said shaft, so obtaining a perfectlongitudinal alignment.

This system also may include, between the two components (2) and (3) tobe assembled, an angular radial balance, constituted by a calibratedsteel plug (13) inserted into a suitable hole (15) positioned on theconnecting device (2), from which it extends for a certain length.

Conveniently, in order to couple the head (3) in radial direction tosaid extending plug (13), this system comprises a milling (14) on theupper surface (12) of the head (3), with the same diameter and of athickness corresponding to the above cited extension.

The head, either equipped with cutting or decorating accessories orother, realized according to the present invention, is made so that itcan be simply removed with just one hand in few seconds, without anyneed of specific tools, and replaced with a second head equipped with adifferent blade and/or pen necessary for the next operation, which maybe either a decoration or a different cut or working on anothermaterial.

The main feature of this invention is the extreme manufacturingsimplicity of the device, facilitated by the absence, during work, of anaxial removing component. Accordingly, it can conveniently develop tomeet mechanical requirements in all other directions.

Therefore, this system maintains basic operation of present machinesunchanged and can be easily applied to all existing machines in thepaper sector and, with appropriate adjustments, to all the othermachines with similar mechanical requirements.

In practice, it is sufficient to make adjustments on the apparatusholding the new accessory coupled to a blade or pen, for example, on theconnecting device or other device controlled by the timing belt and therotating engine group. Rotational motion of the head is controlledelectronically on a constant basis, thus obtaining any shape—linear orcurved, circular, elliptical—and providing complete versatility of withall the types of existing machines.

The connecting device, fitted on a rotating vertical shaft, free fromthe coaxial raising system, remains bound axially, providing forcomplete interchangeability.

In one embodiment, perpendicularly to the thickness of the connectingdevice, there are three passing holes, spaced at the same distance, witha diameter suitable to fit three magnets having cylindrical shape withthe same diameter as the holes and a length not exceeding the depth ofthe connecting device.

Of the same diameter, or of a conveniently prefixed diameter, there isan additional passing hole, calibrated for receiving the plug of radialinterference, which will be hereafter described.

The end support, holding a cutting blade or a pen and a supportingwheel, as well as the various devices indicating position, ismechanically structured to have a central calibrated hole, for balancingthe shaft of the connecting device, and an upper surface shaped as ametal plane with surfaces large enough to comprise the area filled bythe magnets. The same upper supporting surface has an opening, with acalibrated diameter, such that the above-mentioned plug disposesangularly the cutting element and, simultaneously, provides for acoupling of the connecting device with the upper surface.

Therefore, it will be sufficient to insert vertically and axially thedevice holding the blade or pen, led by the same shaft as the upperconnecting device and angularly balanced thanks to an angularinterference plug. The assembly is provided by the action of the threemagnets on the upper metal surface of the final support and,accordingly, on the surface of the connecting device, causing a perfectcontact between connecting device and blade support. The plug inside thecalibrated cavity of the support a provides resistance to the appliedcouple, which is very limited due to the specific kind of work.

The extreme facility and rapidity for changing tools will be explainedin greater detail hereafter.

The above described assembly facilitates tool removal, because themagnets have a limited force necessary for the disconnection (whichmeans in the vertical direction towards the working plane), and does notinvolve any risk of disconnection during operation and/or approach ofthe tool, since this external force, acting perpendicularly to thedirection of removal, is actually absent during working and approaching.On the contrary, during cutting, the force axially exerted andtransmitted by the supporting wheel may increase the assembly actionexerted by the magnets.

The invention provides a simple, practical system that can be integratedinto the current machines, maintaining their advantageous features.

Therefore, one embodiment of the invention relates to a system for therapid change of the head in an operating machine, such as equipment forthe cut and/or decoration of passe-partout, or of items made ofcardboard, glass, ceramic or similar, and includes at least one,preferably more than one, magnet or other device generating a magneticfield, capable of exerting an attracting force between at least one head(3) of said machine and at least one device of said machine, where thehead is or can be connected, making this connection stable.

One embodiment of the invention relates to a system wherein at least onemagnet—which means either a ferromagnetic body or an electric machinegenerating magnetic field—is placed between at least one head (3) and atleast one connecting device, like a toothed wheel.

One embodiment of the invention relates to a system wherein at least onemagnet—which means either a ferromagnetic body or an electric machinegenerating magnetic field—is comprised on at least one connectingdevice, for example, shaped like a toothed wheel, where at least onehead (3) is connected.

One embodiment of the invention relates to a system wherein at leastone, preferably more than one, magnet or similar connects, thanks to itsmagnetic attraction, at least one head (3) with at least one connectingdevice (2), connected in turn to the movable arm of the operatingmachine.

One embodiment of the invention relates to a system comprising aconnecting device, like a toothed wheel (2), between operating machineand at least one head (3) of the same machine, which comprises in itsturn at least one, preferably more than one, magnet or similar, havingenough force to keep the head bound even without mechanical blockelements.

One embodiment of the invention relates to a system wherein theconnecting device, like a toothed wheel, is located over the head (3)where it is connected.

One embodiment of the invention relates to a system wherein, in thecutting phase, the axially exerted force increases the force exerted bythe magnet(s), so reducing the risk of a possible separation of the headfrom the connecting device.

One embodiment of the invention relates to a system wherein the forceexerted by the magnet(s) is sufficient to keep the head bound to theconnecting device, but also to be overcome by an opposite force exertedon it even by one hand in an opposite direction to the force exerted bythe magnet(s).

One embodiment of the invention relates to a system wherein saidmagnet(s) is constituted by an electric machine generating a magneticfield that is deactivated in order to remove the head (3). Thus, whensaid magnetic field is annulled, the attraction will cease and the headcan be separated by the connecting device without any need of particularforce.

One embodiment of the invention relates to a system comprising balanceelements between said connecting device, like a toothed wheel, and saidat least one head.

One embodiment of the invention relates to a connecting device, whichmay be shaped like a toothed wheel (2), between operating machine and atleast one head (3) of the operating machine, and which comprises atleast one, preferably more than one, magnet or similar, having enoughforce to keep the head bound even without mechanical block elements.

One embodiment of the invention relates to a connecting devicecomprising at least one, preferably more than one, holes (10) where themagnets (11) are fitted.

Said magnets may be fixed by bonding, fitting, forced assembly or anyother system, which causes their position to be stable.

The shape of the hole (10) is not important, and can be circular or ofany other shape.

In one embodiment, the magnets are comprised inside the thickness of theconnecting device, which may be shaped like a toothed wheel, in order toavoid any obstacle to the coupling of the two contact surfaces, one ofthe connecting device and one of the head (3).

The holes (10) and the related magnets (11) may be more than one,preferably three.

One embodiment of the invention relates to a connecting device, whichmay be shaped like a toothed wheel (2) comprising a hole (15), suitablydirected and calibrated, containing a plug for the angular balance (13),which extends into a groove (14) defined on the surface of the head (3).

One embodiment of the invention relates to a machine head, equipped witha cutting blade (4) and/or pen and/or other accessory necessary for thework performed by the operating machine, which comprises a calibratedhole (16) mated during assembly with the extension of the shaft (8) ofthe connecting device, shaped like a toothed wheel (2) and fitted onsaid shaft, so obtaining a perfect longitudinal alignment.

One embodiment of the invention relates to a machine head comprising amilling (14) made on the upper surface (12) of the head (3), having thesame shape and thickness as the plug (13) of the device (2), so thatsaid plug can enter into it, realizing an angular balance.

The replacement of the head through the above described system can befulfilled either manually or automatically by means of specificmachines. In practice, the manufacturing details may however vary asregards shape, size, position of elements and type of materials used,but still remain within the range of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages of the present invention will be better understood byevery expert in this field by referring to the enclosed drawings, givenas practical examples of the invention but not to be consideredrestrictive.

FIG. 1 is a perspective view of an embodiment of the invention.

FIG. 2 is an exploded view of the embodiment of FIG. 1.

FIG. 3 is an exploded view of a detail of the embodiment of FIG. 1.

FIG. 4 is an assembled view of the detail of FIG. 3.

FIG. 5 is a top view of the connecting device in the embodiment of FIG.1.

FIG. 6 is a top view of the surface of the head facing the connectingdevice in the embodiment of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a perspective assembled view of the operating arm of themachine (1) with vertical movement, approximately perpendicular to theworking plane, with a support (6) of the same arm disposed alongdirection “Y”. The vertical shafts are positioned and supported byradial and axial bearings, as known in the art, and the upper shaft (7)is coupled to a linear actuator to provide movement along the (Y) axis,while the lower shaft, although connected to upper shaft (7), is free torotate. Connecting device (2) is coupled to the lower shaft by means ofa plug (9) or other mechanical system, providing for a vertical movementof the entire system (1) and a free radial movement of the connectingwheel (2), together with the lower head (3) holding the cutting blade(4) and/or the pen as well as the wheel (5).

The rotation around the “Z” axis directs the blade (4) or the penregardless of the relative rigidity of the arm (1). The approachingmovement before a cut or the development of a decoration is a flathorizontal “X” motion, given to the arm by the machine.

FIG. 2 shows the distinctive components of an embodiment of the presentinvention, which allow a simple and fast installation of the head (3),equipped with cutting blade (4). This figure shows an exploded view ofthe internal system (7), provided with relative balances, bearings, andother necessary implements, having in the final rotating portion (8) ofthe shaft a place for plug (9), so as to radially couple the connectingdevice (2).

The two circular shaped flat surface of the connecting device (upper andlower surface of the connecting device) include some passing holes (10)that receive cylindrical magnets (11) with the same diameter and aheight not exceeding the thickness of the connecting device (2).

In order to get a precise angular signal, necessary for the zero settingof the machine regardless of the replacement of the head (3), and asufficient opposition contrasting its rotation, a plug (13) is providedhaving the double function of balance and torque transmission. Axialbalance is guaranteed by the hole (16) on the final support, whichreceives the extending end of the shaft (8), whereas radial position isobtained by mating a related calibrated hole (15) made with suitablediameter, and perpendicularly to the surface of the connecting device(2). Angular stability, even if calibrated magnet (11) were to besomewhat loose, is however ensured by a fitting groove (14), generatedby a milling of calibrated diameter, made on the external side and fornecessary depth, in perpendicular direction, on the upper surface of thehead (3).

The contact surfaces, upper surface of support (12) and lower surface ofconnecting device (2), are flat for maintaining a correct mechanicalalignment of the system.

FIGS. 3 and 4 respectively show the simple linear movement necessary foran operator to couple the head (3). More particularly, FIG. 3 shows thehead (3) removed from the block (1). The head, equipped with centralcalibrated hole (16) provided on the upper surface (12), is inserted bymeans of a simple vertical push, obviously with proper axial balance,which is ensured by the hole (16) on the calibrated extension of theaxis (8), and of the angular balance, by the insertion of the extendingplug (13) in the related place (14).

Therefore, the action of the magnets fitted into the connecting device(2) allows, with extreme simplicity, the assembly of the final cuttingblade or pen, centered on the zero of the machine and suitable directed(FIG. 4).

For a more detailed illustration of this device, FIGS. 5 and 6respectively show the top view of the connecting device (2) and of theupper contact surface of the head (3).

As above described, the connecting (2) comprises three passing holes(10) of suitable diameter, where the magnets fit by known systems(fitting, forced assembly with interference, etc.) while ensuring thatthe magnets are completely encompassed inside the thickness of theconnecting device (2), in order to avoid any obstacle to the coupling ofthe two contact surfaces.

The connecting device (2) also defines another hole (15), suitablydirected and calibrated, containing, with similar stable assembly, theplug for the angular balance (13), which extends so as to find place ina groove (14) provided on the surface of the head (3), as depicted inthe FIG. 4, which shows a top view of contact surface (12). In thepresent embodiment, contact surface 12 has an essentially rectangularshape and includes a central calibrated hole (16), necessary for theaxial balance of the components, and opening (14), of suitabledimensions, for the angular balance.

What is claimed is:
 1. A system for rapidly changing a head of anoperating machine comprising: a connecting device fitted on a finalportion of a rotating longitudinal shaft of the operating machine, theconnecting device having a substantially planar upper surface facing asubstantially planar surface of the operating machine and asubstantially planar lower surface facing a substantially planar surfaceof the head, a first plug radially locking the connecting device to theshaft; one or more devices generating a magnetic field, the magneticfield operatively and removably coupling the head to the operatingmachine, the one or more devices being disposed within one or moremating longitudinal first openings extending from the upper surface tothe lower surface of the connecting device, the one or more devices notextending beyond the upper and lower surfaces; the rotating longitudinalshaft having an extended portion, the head having a centrally disposedopening shaped to mate with the extended portion of the shaft; and theconnecting device having a second opening configured for receiving asecond plug dimensioned to extend into an outwardly extending recessinto the substantially planar surface of the head, the second plugrotatably coupling the connecting device to the head.
 2. The system ofclaim 1, wherein one or more devices generating a magnetic field are oneor more magnets.
 3. The system of claim 2, wherein the one or moremagnets are three or more magnets.
 4. The system of claim 2, wherein theone or more magnets are ferromagnetic bodies.
 5. The system of claim 2,wherein the one or more magnets are cylindrically shaped.
 6. The systemof claim 1, wherein the one or more devices generating the magneticfield comprise an electric machine generating the magnetic field.
 7. Thesystem of claim 1, wherein the one or more devices not extending beyondthe upper and lower surfaces are flush with the upper and lowersurfaces.
 8. The system of claim 1, wherein the substantially planarupper and lower surfaces of the connecting device, the substantiallyplanar surface of the machine, and the substantially planar surface ofthe head are flat surfaces.